1. Field of the Invention
The present invention relates to a synchronizing method and device of a Management Information Base (hereinbelow abbreviated as MIB) in a Network Management System (hereinbelow abbreviated as NMS). Described in greater detail, a MIB is a database that stores data for the control by a Network Manager (hereinbelow abbreviated NM) of a plurality of Network Elements (hereinbelow abbreviated NE) that are connected to a communication network. The present invention relates to a method and a device for reloading to the MIB back-up data, which have been saved in advance, when the content of this MIB has for some reason been damaged or altered, and moreover, for synchronizing these data with the current information of each NE.
2. Description of the Related Art
In the prior art, message format or communication protocol is stipulated in advance in a communication network to which a multiplicity of NE are connected, and by means of these standards, the NMS manages the various configuration settings and controls for the plurality of NE that make up the communication network. The NMS gathers the management information held by each NE in order to realize this management, and in addition to generating its own management information and registering this information in the MIB, uses this MIB to manage the NE and communication network.
The network management referred to here pertains to controlling the configuration, operation, and maintenance of the communication network, and a NM is constituted by a computer in which are installed application programs for managing the configuration, detecting trouble, and monitoring the performance of the NE and lines on the communication network. On the other hand, the NE each have their own respective specific functions, but as for functions relating to the communication network, are provided with only extremely basic operation functions such as individual control, call processing, and information transfer. NE do not have operation capabilities that exceed this extent.
The NM and NE are normally connected by a control network for transmitting management information apart from the communication network. The NM analyzes and judges data provided from each individual NE by way of this control network, and moreover, executes a series of operations such as instructing each individual NE to carry out specific operations based on the results of analysis and judgment. Usually, only one such NM exists for one network, but the number of NM is not restricted to one, and in the case of a large-scale network, one or more NM may exist according to management zones or functions.
The communication of various settings and control signals between the NM and NE is carried out according to a specific communication protocol that is established for each network. Representative communication protocol types include CMIP (Common Management Information Protocol) that conforms with OSI (Open System Interconnection) established by the ISO (International Organization for Standardization), and the simpler protocol, SNMP (Simple Network Management Protocol).
Taking one case in which SNMP protocol is used as one example, a specific NM and a plurality of NE exist in a network, and the NM transmits commands such as xe2x80x9cget-requestxe2x80x9d and xe2x80x9cset-requestxe2x80x9d established by SNMP, collects management information from each NE, and executes management operations such as configuration management and trouble management by, for example, exchanging setting information.
A MIB in this case is a database for storing management information that is used when network management is carried out by means of OSI management or SNMP. In addition, the stored management information is a logical model of the various NE functions that are necessary elements for management by the NM, and this information includes as attributes identifiers and detailed definitions of function operations. For a NE that switches lines, for example, upon defining the management information that represents the function of the hardware switch and, as the attribute of this information, the operating state of the switch, this NE executes operations such as receiving commands from the NM, informing the NM of operating states, and actually operating the switch. In other words, all information that the NM and NE save relating to management information is referred to as MIB, and the NM can manage the various functions within the NE by means of management information, which is an abstract representation.
Operation that is exercised from the NM upon the NE is executed by designating identification numbers of management information defined in this MIB, using commands such as xe2x80x9cGetxe2x80x9d and xe2x80x9cSet,xe2x80x9d and carrying out a setting operations of the management information of the NE (setting of operating conditions, the starting and halting of operations, as well as the generation, and deletion of the management information itself).
FIG. 1 is a conceptual view showing the positioning of the NM. NM 120 shown in FIG. 1 is connected to each NE on communication network 100 by control network 110 and carries out communication by a specified control protocol.
As a provision against data loss due to failures, back-up data of database MIB 140 that is managed by NM 120 are copied to external storage medium 130 on a regular basis such as, for example, once each week. However, the operations of setting or reading out the values of the various information from NM 120 to the group of NE of communication network 100 is carried out many times every day, and differences in information between the content of MIB data 140 and the content of copied data in external storage medium 130 therefore increase in proportion to the time that elapses from the time of copying of back-up data to external storage medium 130.
For example, a case is explained in which the data of MIB 140 of NM 120 becomes unusable due to some type of trouble. At this time, the back-up data stored beforehand in external storage medium 130 are restored to MIB 140 of NM 120. In other words, when back-up data are reloaded to the machine memory during operation, the information in the memory of NM 120 is su overwritten by the back-up data. In this case, there is a high possibility that information that is currently set in the NE differs from the information at the time the back-up data were copied, and there is consequently a danger of a variety of new problems occurring due to conflicts in data if operations are continued with this unaltered data.
Assuming that the restored data are data that were saved in external storage medium 130 from MIB 140 one week previously, in a worst case, the information of all NE being managed may become non-current. If several hundred NE are being managed by the NM in question, processing was consequently required for uploading information from this number of NE to synchronize the MIB data that were restored by the data of the previous week with the most recent information.
Japanese Patent Laid-open No. 186686/97 and Japanese Patent Laid-open No. 265426/97 are examples of the prior art that disclose similar database synchronization methods.
Japanese Patent Laid-open No. 186686/97 discloses the establishment of duplicate NM in which the occurrence of differences in the databases respectively managed by an active NM and a standby NM is prevented by periodically sending network management information from the active NM to the standby NM to synchronize the two NM.
Japanese Patent Laid-open No. 265426/97, on the other hand, discloses a database synchronizing method in which, when a database is distributed between the management system and a plurality of managed systems, the structuring and restructuring of each database is simplified by mutually exchanging system configuration information between the management system and managed systems to build a database having a tree structure. This published gazette, however, does not touch on a method for simplifying synchronization in the event of inconsistencies in states between the managing system and managed systems.
Theoretically, in the case of data synchronization for matching the content of a database that has been restored by back-up data to the current states within the network, information must be uploaded only from the NE in which states have been modified following update of back-up data. To realize this processing, however, the operator that carried out the operation must store or record what time and to which NE modifications were made. In addition, if there are more than one operator of the NM, all of these records must be compiled. The memory of all operators or a hard-copy record sheet is impossible to monitor, and this inability was a cause of faulty operation. In particular, in a large-scale communication network in which the states of each NE are modified at high frequency, there was the problem that NE with inconsistent management information occur at a high rate despite frequent collection of back-up data, and management was therefore difficult.
It is an object of the present invention to provide a network management system that enables synchronization of discrepancies in information between an operation database, i.e., an MIB, and NE with the minimum amount of processing and that allows the NM to resume management operations, even in cases in which the MIB is restored by past back-up information.
To achieve the above-described object, the present invention uses a database information managing unit provided within the NM to compare information stored in the MIB with information stored in NE, automatically detect NE for which discrepancies in data may exist, and upload the necessary information from only those NE even in a case in which the MIB is restored by back-up data to past information.
In other words, the database synchronization system of a network management system according to the present invention relates to a NM that manages a plurality of NE by modifying, by way of a control network, the stored xe2x80x9cmanagement informationxe2x80x9d and xe2x80x9cdatabase informationxe2x80x9d of each NE, i.e., the xe2x80x9cinformation defining the functions of each NExe2x80x9d and xe2x80x9cinformation showing the history of modifications of the times the content of management information of each NE was rewrittenxe2x80x9d; and includes the following means:
(1) an MIB for storing, corresponding to each NE, the management information and database information that are stored by each NE, as well as for periodically saving back-up data of the stored information;
(2) a NM control unit for, as the management operations of each NE, both modifying the setting content of management information stored in that NE and updating the management information content corresponding to that NE that is stored in the MIB to the same content;
(3) a database information managing unit for, when management operations for each NE are to be executed, i.e., when management information is to be modified, after the stored information of the MIB has been substituted by back-up data, first comparing the database information stored in the NE with the database information stored in the MIB that corresponds to that NE before setting the new management information, and if a discrepancy is detected in this comparison process, using the management information stored in that NE to update the corresponding management information of the MIB, and then eliminating that NE as an object of the database information comparison process until the stored information of the MIB is next substituted by back-up data.
In a case in which the MIB is substituted by back-up data and the version of the data becomes old, the NM uses a database information managing unit to compare the MIB information with the information of the NE before modifying the settings of the NE management information, and if discrepancies exist, updates the management information of the MIB to the management information of the NE.
In addition, when the database synchronizing system of the NMS of the present invention receives notice of recovery from a failure from a NE that has reported the occurrence of trouble, and the settings of the management information for managing that NE are to be modified, the above-described database information managing unit may compare the database information that is stored in that NE with database information of the MIB that corresponds to that NE, and if a discrepancy is detected, the management information of the NE may be updated to the corresponding management information of the MIB.
The NM of the present invention thus updates the management information of the NE using management information of the MIB when discrepancies in the management information are detected due to trouble originating in the NE.
In addition, the database information that corresponds to management information includes, as an access record: the access time, which is the time that the management information of a NE was accessed from a NM; an accessing NM identifier, which is the identifier of the NM that accessed the management information of the NE, and an accessed NE identifier which is the identifier of the NE that was accessed.
Upon detecting various events indicating trouble of the NM and NE, the NM control unit of this invention analyzes the event, divides the events between trouble originating in the NM, trouble originating in a NE, and compound problems of both, and carries out database synchronization in accordance with the category of the problem.
As explained hereinabove, when carrying out management operations with respect to each NE, the present invention first determines whether or not the management information of the relevant NE is synchronized with the data held by the NE and the data held by the MIB by comparing each database information that corresponds to the two sets of management information, and if not synchronized, synchronizes with the most recent management information, thereby allowing the operator to carry out normal operations without keeping track of the state of synchronization of the contents of each NE and MIB. Even in a case in which the MIB has been restored by back-up data and becomes an older version, for example, the data are automatically corrected and the operator is relieved of the unnecessary burden of updating the data.
Once the synchronization has been carried out for a NE, a synchronization process need not be repeated until the next time the MIB is restored, and moreover, an unnecessary burden is not placed on the system because no synchronization processes are performed for a NE that has not undergone any control operations.
Even in a case in which the management information that is stored in a NE is changed in its entirety due to, for example, a unit exchange, the NM distinguishes the necessity for a synchronization process based on the trouble category reported from the NE and performs synchronization distinguishing between cases that urgently require synchronization and cases that allow synchronization to be carried out separately. Accordingly, the operator of the NM can carry out operations without keeping track of the status of each NE within the communication network, and a network management system can be realized that places no unnecessary burden on the operator.
Finally, analyzing events that occur, such as trouble that is detected by the NM, determining whether the source of discrepancies in management information is the NM or the NE, and automatically activating the process of synchronizing the database enables a reduction of the manual synchronization work performed by the operator in the prior art and allows greater processing efficiency.
The above and other objects, features, and advantages of the present invention will become apparent from the following description referring to the accompanying drawings which illustrate the examples of the preferred embodiments of the present invention.